// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef NET_NQE_EXTERNAL_ESTIMATE_PROVIDER_H_
#define NET_NQE_EXTERNAL_ESTIMATE_PROVIDER_H_

#include <stdint.h>

#include "base/macros.h"
#include "base/time/time.h"
#include "net/base/net_export.h"

namespace net {

// Base class used by external providers such as operating system APIs to
// provide network quality estimates to NetworkQualityEstimator.
class NET_EXPORT ExternalEstimateProvider {
public:
    class NET_EXPORT UpdatedEstimateDelegate {
    public:
        // Will be called with updated RTT, downstream and upstream throughput (both
        // in kilobits per second) when an updated estimate is available. If |rtt|
        // is unavailable, it is set to base::TimeDelta(). If
        // |downstream_throughput_kbps| or |upstream_throughput_kbps| are
        // unavailble, they are set to -1, respectively.
        virtual void OnUpdatedEstimateAvailable(
            const base::TimeDelta& rtt,
            int32_t downstream_throughput_kbps,
            int32_t upstream_throughput_kbps)
            = 0;

    protected:
        UpdatedEstimateDelegate() { }
        virtual ~UpdatedEstimateDelegate() { }

    private:
        DISALLOW_COPY_AND_ASSIGN(UpdatedEstimateDelegate);
    };

    ExternalEstimateProvider() { }
    virtual ~ExternalEstimateProvider() { }

    // Returns true if the estimated RTT duration is available, and sets |rtt|
    // to the estimate.
    virtual bool GetRTT(base::TimeDelta* rtt) const = 0;

    // Returns true if the estimated downstream throughput (in Kbps -- Kilobits
    // per second) is available, and sets |downstream_throughput_kbps| to the
    // estimate.
    virtual bool GetDownstreamThroughputKbps(
        int32_t* downstream_throughput_kbps) const = 0;

    // Returns true if the estimated upstream throughput (in Kbps -- Kilobits
    // per second) is available, and sets |upstream_throughput_kbps| to the
    // estimate.
    virtual bool GetUpstreamThroughputKbps(
        int32_t* upstream_throughput_kbps) const = 0;

    // Returns true if the time since network quality was last updated is
    // available, and sets |time_since_last_update| to that value.
    virtual bool GetTimeSinceLastUpdate(
        base::TimeDelta* time_since_last_update) const = 0;

    // Sets delegate that is notified when an updated estimate is available.
    // |delegate| should outlive |ExternalEstimateProvider|.
    virtual void SetUpdatedEstimateDelegate(
        UpdatedEstimateDelegate* delegate)
        = 0;

    // Requests an updated network quality estimate from the external estimate
    // provider.
    virtual void Update() const = 0;

private:
    DISALLOW_COPY_AND_ASSIGN(ExternalEstimateProvider);
};

} // namespace net

#endif // NET_NQE_EXTERNAL_ESTIMATE_PROVIDER_H_
